Sorry I'm no help on why your steps won't go in. As far as the extra wire, I installed a new controller on mine. It had an extra wire. Said it was for the porch light. When connected it would turn the light on and off when the steps came out and in.
My steps where drawing power when not in use. After a couple days it would drain the house batteries. My local RV guy offered to replace the controller with a used one for $80. + labor. He said that was half price. I found the exact controller on Amazon. New for $75.00. Installed it myself. Haven't had a problem since.